Swivel for use in installing large diameter casing

ABSTRACT

The invention includes a pair of swivels for use with an auger boring machine. One of the swivels allows for rotation of a first auger of a first auger assembly connected to the trailing end of a pilot tube without rotating the pilot tube. The other swivel allows for rotation of a larger diameter second auger connected to the trailing end of the first auger assembly without rotating the first auger. Each of the swivels includes a thrust bearing.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/715,134, filed Mar. 7, 2007; the disclosure of which is incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Technical Field

The invention relates generally to an auger boring machine and a methodof use in the trenchless installation of underground pipe. Moreparticularly, the invention relates to such a machine which utilizes apilot tube for forming a pilot hole for guiding smaller and largerdiameter augers of the machine. Specifically, the invention relates to aswivel between the pilot tube and smaller diameter auger and a swivelbetween the smaller and large diameter augers.

2. Background Information

The use of an auger boring machine for installing underground pipebetween two locations without digging a trench there between is broadlyknown. In addition, it is known to use a pilot tube formed of aplurality of pilot tube segments to create a pilot hole for guiding anauger which bores a larger hole so that the auger remains within areasonably precise line and grade. For example, see U.S. Pat. No.6,206,109 granted to Monier et al. An enormous amount of force isinvolved in driving the pilot tube and in rotating the augers. Duringthe driving of the pilot tube, the pilot tube is rotatable to providesteering in order to keep the pilot tube on a reasonably accurate lineand grade. However, once the pilot hole is completed, there is no longera need to rotate the pilot tube and continuing such rotationsubstantially adds to the amount of force required in the auger boringprocess. Similarly, once it is time for the larger diameter auger andcutting head to begin cutting the larger diameter hole, there is no needto continue rotation of the smaller diameter auger which likewiserequires additional force. The present invention solves this and otherproblems in the art.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a method comprising the steps of: pushinga smaller diameter cylindrical casing forward with a first section of aswivel through an underground hole having a first diameter; and duringthe step of pushing, rotating a second section of the swivel, a firstcutting head rearward of the smaller diameter casing and a first augerrearward of the first cutting head relative to the first section andsmaller diameter casing to enlarge the underground hole from the firstdiameter to a second diameter larger than that of the smaller diametercasing.

The present invention also provides a method comprising the steps of:rotating a smaller cutting head and smaller auger of a smaller augerassembly to cut an underground hole having a first diameter; mounting afirst section of a swivel on a trailing end of the smaller augerassembly after the underground hole with the first diameter has beencut; and rotating a second section of the swivel, a larger cuffing headand a larger auger of a larger auger assembly relative to the firstsection to enlarge the underground hole from the first diameter to asecond diameter larger than the first diameter.

The present invention further provides a method comprising the steps of:pushing a swivel forward with a first auger assembly through anunderground hole having a first diameter; the swivel comprising firstand second sections mounted on one another with relative rotationtherebetween; the first auger assembly comprising a first cutting headand a first auger; during the step of pushing, rotating the secondsection, first cutting head and first auger relative to the firstsection to enlarge the underground hole from the first diameter to asecond diameter larger than the first diameter; the step of rotatingcomprising the step of rotating the first auger within a cylindricalcasing having a diameter larger than that of the first diameter; andmoving the casing forward into the enlarged underground hole.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a side elevational view of the auger boring machine of thepresent invention shown in a pit formed in the earth.

FIG. 2 is a top plan view of the auger boring machine.

FIG. 3 is a side elevational view similar to FIG. 1 showing the pilottube drive assembly removed from the frame of the boring machine.

FIG. 4 is a perspective view of the drive assembly.

FIG. 5 is a fragmentary sectional view taken along the longitudinal axisof a pilot tube segment showing the internal structure thereof and thecoupling members.

FIG. 6 is an end elevational view taken on line 6-6 of FIG. 5 showingone of the coupling members.

FIG. 7 is an end elevational view taken on line 7-7 of FIG. 5 showingthe other coupling member.

FIG. 8 is a side elevational view of the auger boring machine showingthe smaller diameter auger assembly mounted on the pilot tube by thefirst swivel.

FIG. 8A is similar to FIG. 8 and shows the larger diameter augerassembly mounted on the smaller diameter auger assembly by the secondswivel.

FIG. 9 is a sectional view taken on line 9-9 of FIG. 8 showing theconnection between the pilot tube segments via the connection of thecoupling members.

FIG. 10 is sectional view taken on line 10-10 of FIG. 8 showing theinternal structure of the first swivel and connections with the pilottube and smaller diameter cutting head.

FIG. 11 is an enlarged fragmentary view of the second swivel connectedto each of the smaller and larger diameter auger assemblies.

FIG. 12 is a sectional view taken on line 12-12 of FIG. 11 showing theinternal structure of the second swivel and its connections with thesmaller and larger diameter auger assemblies.

FIG. 13 is a top plan view of the drive mechanism showing an extensionof the hydraulic actuators to provide an initial stage of pilot holeformation and also showing the steering capability of the pilot tube.

FIG. 14 is similar to FIG. 13 and shows the subsequent pilot tubesegment connected to the previously driven pilot tube segment and thedrive mechanism.

FIG. 15 is similar to FIG. 14 and shows the extension of the hydraulicactuators of the drive mechanism to drive the pilot tube with the newlyinstalled pilot tube segment thereof to lengthen the pilot hole.

FIG. 16 is a side elevational view of the boring machine showing thepilot tube drive assembly being removed from the frame of the augerboring machine.

FIG. 17 is similar to FIG. 16 and shows the auger and first swivelconnected to the smaller diameter auger assembly and pilot tube.

FIG. 18 is similar to FIG. 17 and shows the smaller auger assemblyboring an intermediate diameter hole as it follows the pilot tube.

FIG. 19 is similar to FIG. 18 and shows a second segment of the smallerdiameter auger assembly having been connected to the first segment andmounted on the auger drive.

FIG. 20 is similar to FIG. 19 and shows additional boring with thesubsequent segment of the smaller diameter auger assembly to lengthenthe intermediate diameter hole.

FIG. 21 is similar to FIG. 20 and shows the installation of the largerdiameter auger assembly on the auger drive and on the smaller diameterauger assembly via the second swivel.

FIG. 22 is similar to FIG. 21 and shows the larger diameter augerassembly boring at an initial stage of the enlarged diameter hole inwhich the underground pipe will be disposed.

FIG. 23 is similar to FIG. 22 and shows the larger diameter holecompleted with the pipe disposed therein.

FIG. 24 is similar to FIG. 8 and shows the smaller diameter augerassembly mounted on a second embodiment of the pilot tube by a secondembodiment of the first swivel and a shock rod.

FIG. 25 is a sectional view taken on line 25-25 of FIG. 24 showing thesecond embodiment of the swivel and its respective connections with thetrailing end of the pilot tube and the leading end of the shock rod.

FIG. 26 is a sectional view taken on line 26-26 of FIG. 24 and shows theconnection between the trailing shock rod coupler and the cutting headcoupler.

FIG. 27 is similar to FIG. 18 and shows a smaller auger assembly boringan intermediate diameter hole as it follows the second embodiment of thepilot tube, first swivel and shock rod.

FIG. 28 is similar to FIG. 27 and shows the smaller auger assemblydisconnected from the shock rod and removed from the intermediatediameter hole.

Similar numbers refer to similar parts throughout the drawings.

DETAILED DESCRIPTION OF THE INVENTION

The auger boring machine of the present invention is indicated generallyat 10 in FIGS. 1 and 2. Referring to FIG. 1, machine 10 is typicallydisposed in a pit 6 formed in the earth's soil or ground 8 andconfigured to bore a hole through ground 8 for the purpose of layingunderground pipe in the bored hole. Machine 10 typically bores a holefrom within a pit such as pit 6 to another pit which may be spacedseveral hundred feet away. Machine 10 includes a frame 12 which extendsfrom a front end 14 to a rear end 16 of machine 10. Front and rear end14 and 16 define there between an axial direction of machine 10. Machine10 further has first and second opposed sides 18 and 20 (FIG. 2)defining there between a lateral direction of machine 10.

An engine compartment 22 is mounted on frame 12 and houses therein afuel powered engine 24, an electric generator 26 powered by engine 24and a hydraulic pump 28 also powered by engine 24. An auger drivecompartment 30 is disposed in front of compartment 22 and houses thereinan auger drive having a rotational output shaft 32 for rotationallydriving an auger 34 (FIG. 25). Frame 12 further includes a pair ofspaced longitudinally extending rails 36 secured to a plurality of crossbars 38 which are mounted on ground 8 in the bottom of pit 6. A pair ofadjustable stabilizing poles 40 are telescopically received in andadjustably mounted respectively on rails 36 and configured to pressagainst the wall of ground 8 which bounds pit 6.

A pilot tube guidance and drive assembly 42 is removably mounted onframe 12 and more particularly on rails 36 via mounting legs 44 (FIG. 3)which are removably insertable into openings 46 formed in each of rails36. Mounting legs 44 and the mounting mechanism of which they are a partare described in further detail in the copending application entitledPilot Tube System And Attachment Mechanism for Auger Boring Machinewhich is incorporated herein by reference and filed concurrentlyherewith. Assembly 42 when mounted on frame 12 is positioned so that acentral axially extending axis X of a pilot tube 48 is coaxial with anaxially extending axis Y which passes centrally through output shaft 32and about which shaft 32 is rotated when driving auger 34. Assembly 42includes a generally circular rear plate 50 which abuts compartment 30when assembly 42 is mounted on frame 12 and includes a portion which isinserted into compartment 30 to assist with the alignment of assembly42.

Assembly 42 includes front and rear mounting assemblies 52 and 54 whichalso serve as supports providing rigid structure extending laterallyacross the width of assembly 42. Assemblies 52 and 54 are seated onrails 36 of frame 12 when assembly 42 is mounted on frame 12. A pair ofaxially extending parallel spaced rails 56 and 58 are rigidly mounted onassemblies 52 and 54 and extend along most of the length of assembly 42.Adjustable stabilizing poles 60 are telescopically mounted respectivelywithin first and second rails 56 and 58 and are adjustable to provideforce against ground 8 in the same manner as poles 40.

A rigid front cross member 62 extends between and is connected to eachof rails 56 and 58 adjacent the front thereof with a front pilot tubesupport 64 mounted thereon centrally between rails 56 and 58. Support 64includes a plurality of bearings which engage the pilot tube 48 to allowaxial movement of tube 48 as well as rotational movement of tube 48about axis X to allow for the steering thereof. Rear plate 50 andassociated structure attached thereto serve as a rear cross member forrigidly connecting rails 56 and 58 to one another at the rear ofassembly 42. An intermediate cross member 66 extends laterally betweenrails 56 and 58 and is supported respectively on rails 56 and 58 byfirst and second roller assemblies 68 and 70 (FIGS. 1 and 3). Eachroller assembly includes a pair of upper rollers 72 and lower rollers 74which respectively rollingly engage upper and lower parallel surfaces 76and 78 of respective rails 56 and 58.

An electric guidance control motor 80 is mounted on cross member 66 forselectively rotating pilot tube 48 in either direction about axis X. Alubricant feed swivel 82 having a lubricant inlet 84 is mounted on motor80 by a pair of spaced mounting rods 86. Swivel 82 serves as an engagingmember for drivingly engaging tube 48 during operation of assembly 42.Inlet 84 of swivel 82 is in fluid communication with a lubricantfeedline which is in fluid communication with a source of lubricant,which is typically water. Swivel 82 receives water through inlet 84 topump the water through pilot tube 48 and through a steering head 88connected to the front of pilot tube 48, the water flowing out a forwardexit opening 90 and a plurality of lateral exit openings 92. A cordcarrier 96 includes a plurality of links 98 which are pivotallyconnected to one another so that electrical cords (not shown) forpowering motor 80 will not become tangled during the driving of pilottube 48.

During the driving of pilot tube 48, a steering mechanism keeps tube 48on line and grade using a theodolite which utilizes a camera 100 inelectrical communication with a display monitor 102 which displays theview of the camera through pilot tube 48 of an illuminated LED target104 (FIG. 4) disposed within pilot tube 48 adjacent steering head 88. Inorder for camera 100 to view LED target 104, pilot tube 48 is hollow, asare the other structures intermediate camera 100 and target 104, such asmotor 80 and swivel 82, in order to provide a line of sight Z (FIGS. 5,9, 13) between camera 100 and target 104. A guidance control unit 106 ismounted on rail 58 and includes manually operable controls 108 inelectrical communication with motor 80 in order to send a signal tomotor 80 to control rotation of pilot tube 48.

Assembly 42 includes a drive mechanism 110 comprising a pair ofhydraulic piston-cylinder combinations 112 which are powered by pump 28and provide a substantial amount of forward and reverse thrust. Forexample, the forward thrust produced by combinations 112 on onepreferred embodiment has a maximum thrust of 280,000 pounds while thereverse thrust has a maximum thrust of 140,000 pounds. Drive mechanism110 is described in greater detail in the copending application entitledMethod And Apparatus For Providing A Continuous Stroke Auger BoringMachine which is incorporated herein by reference and filed concurrentlyherewith.

Pilot tube 48 is made up of a plurality of pilot tube segments which areconnected end to end to sequentially increase the length of pilot tube48 during the driving process. Pilot tube 48 includes lead pilot tubesegment 122, which houses target 104, is connected to steering head 88and is shorter than the standard pilot tube segments 124 connectedsequentially behind segment 122.

As noted previously, pilot tube 48 is configured to allow a lubricantsuch as water to flow therethrough to steering head 88. With referenceto FIGS. 5-7, segment 124 has first and second coupling members 130 and132 having a mating configuration with one another so that a firstcoupling member 130 of tube segment 124 may be coupled to a secondcoupling member 132 of another tube segment 124 to form pilot tube 48during the process of driving the pilot tube. Members 130 and 132 arerespectively connected at either end of a central section 134, whichincludes an outer pipe 135 and an inner pipe 166 defining therebetweenan annular passage 170. Each of outer pipe 135 and coupling members 130and 132 have an outer diameter D1 (FIG. 7) which is the diameter ofpilot tube 48. First coupling member 130 includes an externally threadedend portion 138. Six lubricant passages 140 are formed in first couplingmember 130 and communicate with passage 170. A central hexagonal opening148 extends inwardly from the trailing end of member 130.

Second coupling member 132 includes an inner member 150 and aninternally threaded collar 152 rotatably mounted on inner member 150 andconfigured to threadably engage the threaded portion 138 of a couplingmember 130 of another pilot tube segment 124. Inner member 150 includesa hexagonal segment 158 which is receivable within and has a matingconfiguration with hexagonal opening 148 of first coupling member 130.Inner member 150 includes an annular wall 160 and defines a centralpassage 162 and six lubricant passages 164 communicating with passage170 and arranged to align with passages 140 when a first and secondcoupling member 130 and 132 are joined to one another. Passages 140, 164and 170 thus form a lubricant through passage in tube segment 124extending from adjacent its leading end to adjacent its trailing end.

Inner pipe 166 defines a central passage 168 which communicates withpassage 162 and opening 148 so that a through passage is formed insegment 124 to provide for line of sight Z. FIG. 9 shows two pilot tubesegments 124 connected via the coupling of members 130 and 132 via thethreaded engagement there between. Passages 140 are aligned respectivelywith passages 164 with seals 165 therebetween. The lubrication system ofassembly 42 is described in further detail in the copending applicationentitled Lubricated Pilot Tubes For Use With Auger Boring Machine PilotSteering System which is incorporated herein by referenced and filedconcurrently herewith.

FIG. 8 shows machine 10 with drive assembly 42 removed therefromsubsequent to pilot tube 48 having been driven to form a pilot hole 172extending from pit 6 to another open space such as pit 174. FIG. 8 alsoshows that pilot tube 48 includes a first pilot tube segment 124A and asecond pilot tube segment 124B connected thereto. In addition, a firstsmaller diameter auger assembly 176 is mounted on pilot tube 48 via afirst swivel 178 disposed therebetween. Auger assembly 176 has adiameter D2 (FIG. 11) which is substantially larger than diameter D1(FIG. 7) of pilot tube 48. Assembly 176 includes a cylindrical casing180, auger 34 disposed therein and a cutting head 182 mounted on theleading end of auger 34 and rotatable therewith. Auger 34 is mounted ondrive 32 so that FIG. 8 shows machine 10 in preparation for boring ahole with cutting head 182 which is larger than pilot hole 172.

FIG. 8A shows machine 10 having been operated so that auger assembly 176has formed such a larger diameter intermediate hole 184 in soil 8. FIG.8A also shows that auger assembly 176 includes first and second segments186A and 186B connected thereto. A larger second auger assembly 188 ismounted on the trailing end of first auger assembly 176 via a secondswivel 190. Assembly 188 has a diameter D3 (FIG. 11) which issubstantially larger that diameter D2 of first assembly 176. Assembly188 includes a cylindrical casing 192, auger 194 disposed therein and acutting head 196 mounted on the leading end of auger 194 and rotatabletherewith. Second swivel 190 includes an axially elongated cylindricalmounting insert 198 which is slidably received within the trailing endportion of casing 180 of segment 186B. More particularly, insert 198 isdisposed within the interior cavity in which auger 34 is disposed andslidably engages the inner surface of casing 180 upon insertion therein.Auger 194 is mounted on drive 32 so that FIG. 8A shows machine 10 inpreparation for boring a larger diameter hole than that of intermediatehole 184.

Referring to FIG. 10, first swivel 178 and its connection to pilot tube48 and auger assembly 176 is described in further detail. Swivel 178 hasleading and trailing ends defining therebetween an axial directionthereof. Swivel 178 is configured to allow for the rotation of cuttinghead 182 and auger 34 independent of the movement of pilot tube 48 andtypically without rotation of pilot tube 48. This is achieved primarilyby the use of a pair of axially spaced annular thrust bearings 200A and200B. Swivel 178 thus includes a rotatable portion or section which ismounted on and rotates with cutting head 182 relative to another portionor section of swivel 178 which is referred to herein as the non-rotatingportion for simplicity. More particularly, the rotatable portionincludes a main shaft 202 and a retaining flange or cap 204 mounted onthe leading end of main shaft 202. Shaft 202 is mounted on cutting head182 by a bolt 206 and nut threaded thereon. Cap 204 is secured to shaft202 by a plurality of bolts 208 extending through holes formed in cap204 and threadably engaging shaft 202. Shaft 202 includes a hexagonal orother non-circular projection 210 which extends rearwardly into a matinghexagonal or other non-circular opening formed in cutting head 182 anddefines a hole through which bolt 206 passes. Shaft 202 steps outwardlyfrom projection 10 to a cylindrical flange 212 at the leading end ofprojection 210, then steps inwardly to a cylindrical seal seat 214 andsteps further inwardly to a forward cylindrical portion 216 forward ofseal seat 214. Thrust bearings 200 circumscribe portion 216, abuttingthe cylindrical outer surface thereof. Bearing 200A abuts the trailingend of cap 204 and bearing 200B abuts the leading end of seat 214.Lubricant passages 218 are formed in forward portion 216 to allowmovement of lubricant therethrough which is used in lubricating thrustbearings 200. A rearmost seal 220 abuts the outer cylindrical surface offlange 212, and a pair of seals 222 likewise abut the outer surface ofseal seat 214 with one of seals 222 abutting the rear edge of thrustbearing 200B.

Swivel 178 also includes a non-rotating portion which is mounted onpilot tube 48. The non-rotatable portion includes a main shaft 224 and amounting flange or cap 226 connected to the rear end thereof by aplurality of bolts 228 which threadably engage shaft 224. Moreparticularly, shaft 224 includes a hexagonal or other non-circularforward projection 230 which is received in hexagonal or othernon-circular opening 148 in a mating fashion therewith. Shaft 224further includes an annular flange 232 extending radially outwardly fromthe trailing end of forward projection 230, and a rear projection 234extending rearwardly from flange 232. Flange 232 has a leading or frontend 236 and a trailing or rear end 238. Front end 236 engages seals 165and the trailing end of pilot tube 48 when mounted thereon so thatflange 232 serves as a pushing member for pushing pilot tube 48 duringoperation. Front end 236 thus completely covers entrance openings 239 atthe trailing end of respective passages 140 on the outer surface ofpilot tube 48. Swivel 178 further includes an internally threaded collar240 which threadably engages threaded portion 138 of the rearmostcoupling member 130 of pilot tube 48. Collar 240 has a cylindrical sidewall and an annular flange 242 extending radially inwardly from the rearend of the cylindrical side wall. Flange 242 engages rear end 238 offlange 232 when swivel 178 is mounted on pilot tube 48. An annular wall244 defines an interior chamber in which rear projection 234 isreceived. Wall 244 is secured to cap 226 by a plurality of bolts 246which threadably engage wall 244. Wall 244 further includes a taperedsection 248 which tapers rearwardly and radially outwardly from adjacenttrailing end of collar 240. Wall 244 further includes an externallythreaded portion 250 disposed rearwardly of section 248.

Wall 244 further includes an annular flange 252 extending rearwardlyfrom threaded portion 250 and forming the trailing end of wall 244.Flange 252 defines therewithin a cavity which serves as a counter bore254 in which mounting cap 226 is received in abutment with a rearwardlyfacing counter bore ledge 256 which bounds counter bore 254. The headsof bolts 246 and 208 are disposed within counter bore 254 with bolts 208disposed radially inwardly of bolts 246 to prevent interferencetherebetween during rotation of cutting head 182 and the rotatableportion of swivel 178. An outwardly facing annular groove is formed inthe outer surface of flange 252 for receiving therein an annular seal258.

The non-rotating portion of swivel 178 further includes a centralgenerally cup-shaped connecting member 260 which includes a base 262 anda cylindrical side wall 264 extending forward therefrom. Side wall 264at the front thereof includes an internally threaded portion 266 whichthreadably engages threaded portion 250 to secure member 260 to annularwall 244 with an inner surface of side wall 264 abutting seal 258 toprovide a seal between the two members. Member 260 defines an interiorchamber 268 with which an externally accessible lubricant access port270 communicates. The front of forward portion 216 and retaining cap 204of the rotatable portion of swivel 178 are disposed within interiorchamber 268 along with thrust bearing 200A. Base 262 includes anexternally threaded portion 272 and defines an annular groove along itsouter surface rearward of portion 272 for receiving therein an annularseal 274. The non-rotating portion of swivel 178 further includes a rearconnecting member 276 comprising a substantially cylindrical side wallhaving an internally threaded portion 278 at the front thereof whichthreadably engages threaded portion 272 of central connecting member260. The inner surface of connecting member 276 immediately behindthreaded portion 278 abuts seal 274. An inwardly facing annular grooveis formed in member 276 adjacent the rear end thereof for receivingtherein seal 220. The inner surface of member 276 also abuts seals 222.The inner surface of connecting member 276 cooperates with the rearfacing surface of base 262 of member 260, the forward facing surface ofseal seat 214 and the outer circumference of forward portion 216 todefine an annular interior chamber 280 in which thrust bearing 200B isdisposed. An externally accessible lubricant access port 282communicates with interior chamber 280.

Referring to FIG. 12, second swivel 190 is described in further detail.Swivel 190 has leading and trailing ends defining therebetween an axialdirection thereof. Swivel 190 includes a rotatable portion or sectionwhich is mounted on cutting head 196 and rotatable therewith relative toanother portion or section of swivel 190 referred to herein as anon-rotating portion for simplicity. The non-rotating portion is mountedon casing 180 of auger assembly 176. Insert 198 is part of thenon-rotating portion and includes a cylindrical side wall 284 and an endwall 286 connected to the front of side wall 284. Side wall 284 has anouter diameter substantially the same as that of auger 34. It is notedthat the only connection between swivel 190 and the rearmost casing 180is the simple insertion of insert 198 and abutment of pushing plate 288against the trailing end of said casing 180. Thus, there are nofasteners extending between swivel 190 and casing 180 to connect swivel190 to casing 180, nor other fasteners used in the connection. Insert198 thus extends into the interior chamber of the rearmost casing 180 toprovide sufficient stability to the connection. Slidable removal ofinsert 198 from within casing 180 involves no more than frictionalengagement between the cylindrical outer surface of insert 198 and thecylindrical inner surface of casing 180.

A pushing member in the form of an annular pushing plate 288 isconnected to the rear of side wall 284 and abuts the trailing edge ofcasing 180 along its outer perimeter. Plate 288 defines a centralopening in which a cylindrical inner pipe 290 is disposed. Inner pipe290 has a rear threaded portion 291 on which a nut 293 is threadablymounted. An annular flange 292 extends radially outwardly from the frontend of inner pipe 290 and is mounted on plate 288 in abutment with thefront surface thereof by a plurality of bolts 294. An annular cup 296 isdisposed on the rear side of plate 288 and includes an annular base 298and a cylindrical side wall 300 connected thereto and extendingrearwardly therefrom. Cup 296 is connected to plate 288 by a pluralityof bolts 302. Cup 296 defines therein a rearward facing cylindricalcavity 304 for receiving therein a portion of a thrust bearing 306. Acylindrical rear side wall 308 having the same outer diameter as casing180 is connected to and extends rearwardly from plate 288. An externallyaccessible lubrication port 310 is mounted on side wall 308.

The rotating part of swivel 190 includes a hexagonal rear projection 312which is received within a mating hexagonal opening of cutting head 196and mounted thereon via a bolt 314 and nut mounted thereon. A cup-shapedportion 316 is connected to the front end of projection 312 and includesan annular base 318 which extends radially outwardly from projection 312and an annular side wall 320 which extends forward from the outerperimeter of base 318. An annular seal plate 322 is connected to thefront of side wall 320 by a plurality of bolts 324. Plates 322 defines acentral opening in which a portion of inner pipe 290 is disposedimmediately forward of threaded portion 291. Plate 322 along the centerperimeter defines a rearwardly opening notch in which a pair of annularseals 326 are disposed in abutment with each of plate 322 and the outersurface of inner pipe 290. The rearward seal is also abutted by nut 293.An interior chamber 328 is defined by the inner surface of rear sidewall 308 in cooperation with plates 288 and 322, annular cup 296 and theouter surface of pipe 290. Thrust bearing 306 is disposed in interiorchamber 328 in abutment with plate 322, pipe 290 and cup-shaped member296.

The operation of boring machine 10 is now described with reference toFIGS. 13-23. FIGS. 13-15 are shown without main frame 12 of machine 10for simplicity. FIG. 13 shows assembly 42 in the process of driving ofpilot tube 48 to form a pilot hole 172 with an operator 330 operatingassembly 42. More particularly, pistons 116 are extended to drive pilottube 48 into ground 8 as indicated at arrow E in FIG. 13. During theextension of pistons 116 and pilot tube 48, camera 100 senses orreceives input from LED target 104 and relays the images ofilluminations from target 104 to monitor 102. Operator 330 views displaymonitor 102 in order to determine whether steering head 88 needs to beadjusted to maintain the line and grade of pilot tube 48. Operator 330will use controls 108 in order to make any necessary adjustments,specifically rotating pilot tube 48 as indicated at arrow F in FIG. 13via motor 80. For use with longer pilot holes, machine 10 may includeadditional steering control mechanisms, as described in further detailin the copending application entitled Auger Boring Machine WithTwo-Stage Guidance Control System which is incorporated herein byreferenced and filed concurrently herewith. Simultaneously with drivingand steering pilot tube 48, water may be pumped through pilot tube 48via swivel 82 to steering head 88 and through the exit openings thereofin order to facilitate the formation of pilot hole 206.

Once the initial driving of tube 48 is performed, pistons 112 areretracted and a pilot tube segment 124B is positioned and connected totube segment 124A and rotatable portion 186 of swivel 82 as indicated atarrow H in FIG. 14 in preparation for additional driving of tube 48.Drive mechanism 110 is then operated to drive pilot tube 48 includingsegments 124A and B to lengthen pilot hole 172 as indicated at arrow Jin FIG. 15 while operator 330 provides any rotational adjustment tosteering head 88 as indicated at arrow K. The pattern of adding tubesegments and continuing to drive pilot tube 48 goes on until the pilothole is completed or more particularly so that the pilot tube 48 extendsout of ground 8, as at pit 174, so that sections of pilot tube 48 may beremoved as the auger boring operation is underway and thus moves pilottube 48 gradually forward.

Once pilot hole 206 is completed, assembly 42 is removed from frame 12of auger boring machine 10 as indicated at arrow L in FIG. 16. As shownin FIG. 17, auger 34 is then connected to output shaft 32 along with thepipe or casing 180 in which auger 34 is disposed and cutting head 182connected to the front of auger 34. Swivel 178 is also connected to thetrailing end of pilot tube 48 and the front of cutting head 182 to allowfor the rotation of auger 34 and cutting head 210 independently of andgenerally without rotating pilot tube 48. As shown in FIG. 18, engine 24is then operated to rotate output shaft 32, auger 34 and cutting head182 (arrow N) as engine 24 moves forward on rails 36 with auger 34 asindicated at arrow P to form a larger diameter hole 332 in which casing180 will be disposed to form underground piping. Auger 34 carries soildisplaced by cutting head 182 rearwardly to discharge from its trailingend so that it can be removed from pit 6. As shown in FIG. 19, engine 24then moves rearwardly along rails 36 (Arrow Q) so that another casing180 with auger 34 disposed therein is connected (Arrow R) to theprevious casing 180 and auger 34 in end to end fashion to increase thelength of the pipe to be laid, each casing 180 being welded to thesubsequent casing 180. Once the additional casing 180 and auger 34 areconnected, engine 24 is once again operated to rotate output shaft 32and said augers to lengthen hole 332 as indicated at arrow S in FIG. 20.Additional casings 180 and augers 34 are connected and operated byengine 24 until casings 180 reach pit 174, where they are removed fromone another and from pit 174.

As shown in FIG. 21, second auger assembly 188 is then connected to therear of first auger assembly 176 (arrow T). More particularly, insert198 is slidably inserted into the rear of the last of casings 180 sothat pushing plate 288 abuts the trailing end thereof. Cutting head 196is connected to second swivel 190 and auger 194 (not shown) is connectedto output shaft 32. Referring to FIG. 22, engine 24 is then operated torotate shaft 32, auger 194 and cutting head 196 (arrow U) to cut a hole334 which is substantially larger than hole 332 as engine 24 and secondauger assembly 188 move forward as indicated at arrow V. During theprocess of cutting hole 334, pushing plate 288 pushes against thetrailing edge of rearmost casing 180 to push it through hole 332. Swivel190 allows for the rotation of cutting head 196 and auger 194independently of and without rotation of auger 34 within casing 180. Asshown in FIG. 23, an additional casing segment 192 with an auger (notshown) disposed therein is connected to the rear of the first casing 192with the auger connected to drive 32 and then advanced in the samemanner as indicated at arrow W. Additional casings 192 and augers 194are added in sequence and moved along to lengthen hole 334 untilreaching pit 174, at which time casing segments 192 together form thefinal underground pipe. Cutting head 186 and augers 194 are then removedfrom within casing 192. It is noted that engine 24 serves as a singlepower source for operating augers 34 and 194 as well as for powering thedrive mechanism of the pilot tube control and guidance assembly viagenerator 26 and hydraulic pump 28 (FIG. 2), as described in furtherdetail in the copending application entitled Auger Boring Machine WithIncluded Pilot Tube Steering Mechanism which is incorporated herein byreferenced and filed concurrently herewith.

Referring to FIG. 24, the second embodiment of the swivel 336 andassociated structure is now described. Swivel 336 serves the samefunction as that of swivel 178 and is shown connected to the trailingend of a pilot tube segment 338 which is described in greater detail inthe previously mentioned copending application entitled Lubricated PilotTubes for Use With Auger Boring Machine Pilot Steering System. Whileswivel 178 was shown connected directly to a coupler of a cutting head,swivel 336 is connected indirectly to the cutting head via connectionwith a shock rod 340 which is connected to the trailing end of swivel336. In turn, shock rod 340 is connected to a cutting head coupler 342.

Referring to FIG. 25, swivel 336 and its associated connections aredescribed in greater detail. The leading end of swivel 336 is connectedto a coupling member 344 on the trailing end of pilot tube segment 338.Coupler member 344 includes an annular member 346 having an externallythreaded section 348 adjacent its trailing end with a hexagonal cavityor passage 350 extending forward from its trailing end. Swivel 336includes a front coupling member including an annular member 352 and aninternally threaded collar 354 which is rotatably mounted thereon andthreadedly engages threaded section 348 to connect swivel 336 to pilottube segment 338. A hexagonal cavity 356 is formed in annular member352. A hexagonal drive shaft 358 is disposed within hexagonal cavities350 and 356 and has a mating configuration therewith in order to providea torque drive therebetween. Swivel 336 includes a hexagonal projection360 adjacent its trailing end which is matingly received within a frontcavity 362 of an annular coupler 364 of shock rod 340. Front cavity 362is shaped to provide for a driving torque engagement with projection360. A connector pin 366 extends through respective holes formed incoupler 364 and projection 360 to connect the two and provide anadditional torque connection.

With continued reference to FIG. 25, swivel 336 is further described.Swivel 336 includes first and second portions 368 and 370 which aremounted on and rotatable relative to one another via a plurality ofangular contact bearing assemblies including a front annular bearingassembly 372 and six rear angular contact bearing assemblies 374. Firstportion 368 includes an annular member 352, a tapered member 376 rigidlyconnected to member 352 and an outer sleeve 378 connected to taperedmember 376. Tapered member 376 includes an externally threaded portion380 adjacent its trailing edge which threadedly engages an internallythreaded leading portion 382 of outer sleeve 378 to provide theconnection therebetween. Outer sleeve 378 steps inwardly at an annularflange 384 to provide a forward-facing surface or ledge 384 and arearward-facing surface or ledge 386.

Second portion 370 includes projection 360, a cylindrical flange 388extending outwardly from the leading end thereof and a cylindrical shaft390 which is stepped inwardly from flange 388 and extends forwardtherefrom. A pair of annular seals 392 are disposed respectively inannular grooves formed in the cylindrical outer surface of flange 388 toprovide a seal with the inner surface of outer sleeve 378. Flange 388provides an annular forward-facing surface or ledge 394.

A retaining mechanism 396 or flange is connected adjacent the leadingend of shaft 390 and abuts front contact bearing assembly 372 so thatassembly 372 is sandwiched between the trailing end of mechanism 396 andledge 384. Mechanism 396 may include a nut which threadedly engages thefront of shaft 390 or may include a clip or other suitable connector orretaining structure to prevent rearward movement of second portion 370relative to first portion 368.

Each of bearing assemblies 372 and 374 includes an inner ring 398, anouter ring 400 and a full complement of spherical ball bearings 402disposed therebetween. Each of inner rings 398 abuts and rotates withshaft 390. Each of outer rings 400 abuts the cylindrical inner surfaceof sleeve 378 and rotates therewith. Ball bearings 402 thus provide forthe rotatable relation between first and second portions 368 and 370.The inner ring 398 of front bearing assembly 372 abuts retainingmechanism 396 and the outer ring 400 thereof abuts ledge 384. The outerring 400 of the leading rear bearing assembly 374 abuts ledge 386 whilethe inner ring 398 of the trailing or rearmost bearing assembly 374abuts ledge 394. Bearing assemblies 374 are stacked in abutment with oneanother in order to handle the substantial thrust which occurs duringoperation of machine 10 as the cutter head which rotates second portion370 of swivel 336 cuts through the soil and forces a pilot tube forward.This forward force is thus transmitted from pushing surface 394 tobearing assemblies 374 to first portion 368 via pushing surface 386 offlange 388. It is noted that only a single bearing assembly 372 isdisposed forward of flange 388. If a rearward force were applied to movethe pilot tube out of the pilot hole, additional assemblies 372 wouldtypically be stacked ahead of flange 388 to handle the rearward thrust.However, as described below, this is not necessary with the presentsystem.

Referring to FIG. 26, the connection between shock rod 340 and thesmaller diameter auger assembly is described in greater detail. Shockrod 340 has a central section 404 and rear coupler 406 connected to thetrailing end thereof. Coupler 406 includes a projection or insert 407comprising a hexagonal section 408 and a conical section 410 connectedto and extending rearwardly from section 408. Conical section 420 tapersrearwardly and inwardly to a point. A receiving cavity 412 is formed incoupler 342 and includes a leading tapered section 414 which tapersrearwardly and inwardly a short distance to an engaging section 416 of amating configuration with hexagonal section 408 to provide for a torquedrive connection. Section 416 may be hexagonal or another shape ofmating configuration with hexagonal section 408. Insert 407 simplyslides into cavity 412 of coupler 342 with no additional mechanism formaking the connection between coupler 406 and 342. The inner surfaces ofsection 416 engage the outer surfaces of hexagonal section 408 toprovide the torque drive connection between the couplers. However, thereis no other engagement between the two couplers which prevents them fromsliding apart if a suitable force is applied to move the two away fromone another. Thus, there are no fasteners extending between coupler 406and 342 to connect them.

Referring to FIG. 27, the embodiments described with reference to FIGS.24-26 are shown in use with auger assembly 176, which has bored intoground 8 to push the pilot tube ahead of it while swivel 336 allowsfurther rotation of cutting head 182 independent of any rotation of thepilot tube. Should the cutting head of auger assembly 176 become stuckor damaged, it may be necessary to remove the cutting head for repair orreplacement. As illustrated in FIG. 19, this is greatly simplified bythe simple slide fit connection between coupler 406 and 342 wherebymachine 10 is operated to move auger assembly 176 rearwardly out of theintermediate diameter hole cut thereby while leaving the pilot tube,swivel 336 and shock rod 340 within the pilot hole. As previously noted,the ability to leave these elements within the pilot hole eliminates theneed for an increased number of front bearing assemblies 372 withinswivel 336. In addition, this greatly facilitates the ability to repairor replace the cutting head of assembly 176. Without this simpledisconnection between couplers 406 and 342, the entire pilot tube wouldhave to be withdrawn from the pilot hole along with assembly 176 whichwould require a substantial amount of force and energy expendedtherefore. In addition, pilot tube segments which have previously beenremoved at pit 174 would have to be reconnected to the portion of thepilot tube remaining within the pilot hole to ensure that uponsubsequent forward thrust of the pilot tube that it would be properlyaligned within the pilot hole and not be damaged.

Thus, auger machine 10 provides for the driving of a pilot tube andsubsequent connection of a swivel to the pilot tube to allow for therotation of a cutting head and auger independent of the pilot tube inorder to create a hole of increased diameter which follows the pilothole. In addition, machine 10 provides a cutting head having a couplerwhich may be disconnected from the pilot tube while the pilot tuberemains within the pilot hole so that the cutting head may be repairedor removed and replaced if necessary. Moreover, machine 10 provides asecond swivel to allow for independent rotation of a larger diametercutting head and auger independent of the smaller diameter auger. Thisconfiguration greatly facilitates the boring process in the laying ofunderground pipe, minimizing the force required in order to bore therelated holes.

In the foregoing description, certain terms have been used for brevity,clearness, and understanding. No unnecessary limitations are to beimplied therefrom beyond the requirement of the prior art because suchterms are used for descriptive purposes and are intended to be broadlyconstrued.

Moreover, the description and illustration of the invention is anexample and the invention is not limited to the exact details shown ordescribed.

1. A method comprising the steps of: pushing a smaller diameter cylindrical casing forward with a first section of a swivel through an underground hole having a first diameter; and during the step of pushing, rotating a second section of the swivel, a first cuffing head rearward of the smaller diameter casing and a first auger rearward of the first cutting head relative to the first section and smaller diameter casing to enlarge the underground hole from the first diameter to a second diameter larger than that of the smaller diameter casing.
 2. The method of claim 1 wherein the first cutting head and first auger are respectively a larger cutting head and a larger auger of a larger auger assembly; and further comprising the steps of rotating a smaller cutting head and smaller auger of a smaller auger assembly to cut the underground hole having the first diameter; and mounting the first section of the swivel on a trailing end of the smaller auger assembly after the underground hole with the first diameter has been cut.
 3. The method of claim 2 wherein the smaller auger assembly comprises the smaller cylindrical casing; and the step of mounting comprises the step of abutting a trailing edge of the smaller cylindrical casing with the first section of the swivel.
 4. The method of claim 1 wherein the first cutting head and first auger are respectively a larger cutting head and a larger auger of a larger auger assembly; and further comprising the steps of rotating a smaller cutting head and smaller auger of a smaller auger assembly to cut the underground hole having the first diameter; and wherein the step of rotating the second section of the swivel comprises the step of rotating the larger auger without rotating the smaller auger at the same time.
 5. The method of claim 4 wherein the step of rotating the smaller cutting head and smaller auger comprises the step of rotating the smaller auger within the smaller diameter casing.
 6. The method of claim 5 wherein the step of rotating the second section of the swivel comprises the step of rotating the larger auger within a larger diameter cylindrical casing having a diameter larger than that of the smaller diameter casing.
 7. The method of claim 1 wherein the step of rotating comprises the step of rotating the first auger within a larger diameter cylindrical casing having a diameter larger than that of the smaller diameter casing.
 8. The method of claim 7 further comprising the step of moving the larger diameter casing forward into the enlarged underground hole.
 9. The method of claim 8 wherein the swivel is forward of a leading end of the larger diameter casing throughout the steps of rotating and moving.
 10. The method of claim 7 further comprising the step of rotating a smaller auger within the smaller diameter casing.
 11. The method of claim 7 wherein the step of rotating comprises the step of rotating the second section rearward of a trailing end of the smaller diameter casing and forward of a leading end of the larger diameter casing.
 12. The method of claim 7 wherein the step of rotating comprises the step of rotating the second section, first cutting head and first auger with an auger drive which is rearward of a trailing end of the larger diameter casing.
 13. The method of claim 1 wherein the first cutting head has an outer diameter which is greater than an outermost diameter of the first auger.
 14. The method of claim 1 further comprising the step of inserting a wall of the first section into the smaller diameter casing so that a cylindrical outer surface of the wall abuts a cylindrical inner surface of the smaller diameter casing.
 15. The method of claim 14 further comprising the step of abutting a circular trailing edge of the smaller diameter casing with a circular pushing member connected to the inserted wall and extending radially outwardly of the cylindrical outer surface of the wall.
 16. The method of claim 1 wherein the step of pushing comprises the step of pushing a circular trailing edge of the smaller diameter casing with a circular pushing member of the first section.
 17. The method of claim 1 wherein the step of rotating comprises the step of rotating the second section, first cutting head and first auger with an auger drive; and further comprising the step of moving the auger drive rearwardly relative to the swivel.
 18. The method of claim 17 wherein the step of rotating comprises the step of rotating the first auger within a first larger diameter cylindrical casing having a diameter larger than that of the smaller diameter casing; and further comprising, after the step of moving, the steps of connecting a leading end of a second larger diameter cylindrical casing having a diameter the same as that of the first larger diameter casing to a trailing end of the first larger diameter casing; connecting a leading end of a second auger to a trailing end of the first auger; and rotating the first auger within the first larger diameter casing and the second auger within the second larger diameter casing with the auger drive.
 19. A method comprising the steps of: rotating a smaller cutting head and smaller auger of a smaller auger assembly to cut an underground hole having a first diameter; mounting a first section of a swivel on a trailing end of the smaller auger assembly after the underground hole with the first diameter has been cut; and rotating a second section of the swivel, a larger cutting head and a larger auger of a larger auger assembly relative to the first section to enlarge the underground hole from the first diameter to a second diameter larger than the first diameter.
 20. A method comprising the steps of: pushing a swivel forward with a first auger assembly through an underground hole having a first diameter; the swivel comprising first and second sections mounted on one another with relative rotation therebetween; the first auger assembly comprising a first cutting head and a first auger; during the step of pushing, rotating the second section, first cutting head and first auger relative to the first section to enlarge the underground hole from the first diameter to a second diameter larger than the first diameter; the step of rotating comprising the step of rotating the first auger within a cylindrical casing having a diameter larger than that of the first diameter; and moving the casing forward into the enlarged underground hole. 